Enhancement of electroluminescence in zirconium poly carboxylic acid-based light emitting diodes by bathophenanthroline ligand

Abstract

The reactions of a zirconium salt with 1,2,4,5-benzenetetracarboxylate (btec), bathophenanthroline (Bphen) and thiocyanate ions were synthesized and studied by changing the mole ratio, the order of reactant and their pH. It is found that the coordination mode of btec acid depends on the control of reaction conditions. Monodentate, bidentate and bridging modes were investigated by FT-IR spectroscopy. The structures of Zr(btec) and Zr(btec)(Bphen) complexes were also characterized by UV-Vis, CHN, ICP-AES, (1)H NMR and cyclic voltammetry. The role of Bphen ligand in the photopysical properties of Zr(btec)(Bphen) complexes was investigated by DFT calculation. The photoluminescence (PL) emission of nine Zr(btec) complexes that have two peaks, a sharp and intense band for the first peak from 320 to 430 nm in comparison to the second peak with a less intensity and broadened in the regions of 650-780 nm. PL spectra of twelve Zr(btec)(Bphen) complexes also showed bands at 450, 550, 625 nm. LED devices with Zr complex as emitter layer and the structure ITO/PEDOT:PSS/PVK:PBD/zirconium complex/Al emitted a broad band centered at 550 and 650 originating from the Zr complexes. The EL spectra of Zr(btec) and Zr(btec)(Bphen) complexes indicated a long red shift rather than PVK:PBD blend. We believe that the electroplex occurring at PVK-Zr complexes interface is responsible for the green-red emission in the EL of the device. These observations suggest an important role for the Bphen ligand to improve EL performance.

Synthesis of Mn (III)–porphyrin porous coordination polymers as heterogeneous catalysts for CO2 cycloaddition reaction

“…It is worth noting that the difference values between ν as and ν s of COO − peak (Δν) are much larger than 185 cm −1 (Δν > 95 cm −1 ) in all PCPs, indicating the carboxylate groups coordinate to the metal atom in monodentate mode. [ 27 ]…”

Morphological diversity of Mn(iii) metalloporphyrin-based nano- and microsized CPAs assembled via kinetic and thermodynamic controls and their application in heterogeneous catalysis

“…When the reaction is initiated in DMF at 90 °C, seeds are generated due to the fast interaction between the (porphyrin)Mn(III) biscarboxylic acid and the Co(II) ion and they continue to grow until they are in a solution phase, and these microspheres become less soluble and start to precipitate from the DMF medium. IR spectroscopy analysis of this microsphere showed characteristic bands of carboxyl at 1535 cm −1 for the antisymmetric stretch and 1384 cm −1 for the symmetric stretch with Δv as-sym of 151 cm −1 , indicating the bidentate complex 18 between the carboxylic acid and Co(II) ions (Fig. S2 in the ESI †).…”